Automated skip checker device for sewing machine

Abstract

In an automated skip checker device for sewing machine 1 , a detector device 8 detects a slack portion 3 a of a predetermined length D. The slack portion 3 a definitely corresponds to a skip of a stitch or a disconnection of a sewing thread so as to unerringly carry out the detection with a high accuracy. The detector device 8 of the skip checker device has an air stream provider 19 which transfers a tension to an upper thread 3 as a pneumatic pressure to energize an optoelectronic switch 23 so as to make the detector device 8 structurally compact and cost-saving.

What is claimed is: 
     
       1. An automated skip checker device for a sewing machine which has a sewing needle provided to form stitches on a cloth material, an engagement device provided to give tension to an upper thread passing through a needle hole of said sewing needle as a sewing thread, and a thread take-up lever brought into engagement with said upper thread to reciprocally move in association with said sewing needle,
 said automated skip checker device comprising; 
 a tension provider which transfers a certain amount of tension to said sewing thread in operation, so as to laterally curve said upper thread when a slacked portion appears on said upper thread, and 
 a detector device having a detection member provided to detect a position in which said slacked portion appears, said detector device locating said detection member within a thread route from said engagement device to a tip of said sewing needle, 
 wherein said tension provider being a suction air provider which continuously transfers a vacuum pressure to said sewing thread. 
 
     
     
       2. An automated skip checker device for sewing machine which has a sewing needle provided to form stitches on a cloth material, an engagement device provided to give a tension to an upper thread passing through a needle hole of said sewing needle as a sewing thread, and a thread take-up lever brought into engagement with said upper thread to reciprocally move in association with said sewing needle,
 said automated skip checker device comprising; 
 a tension provider which transfers a certain amount of tension to said upper thread in operation, so as to laterally curve said upper thread when a slacked portion appears on said upper thread, and 
 a detector device having a detection member provided to detect a position in which said slacked portion appears, said detector device locating said detection member within a thread route from said engagement device to a tip of said sewing needle; 
 said tension provider having a guide plate located on a line connecting said thread take-up lever to said sewing needle, 
 a vertical hole provided at a left side of said guide plate in order to pass said upper thread therethrough, and further having an air stream provider having an air-blow pipe provided to be in communication with said vertical hole, through which an air stream is blown against said upper thread to transfer a certain amount of tension to said upper thread when in operation, and 
 an opening provided at a right side of said guide plate to be in a crosswise communication with said vertical hole to face a leading end of said air-blow pipe, 
 said detector device having a light emitting element and a photo element which are space opposed by a distance outside the opening of said guide plate in a juxtaposed relationship with said opening of said guide plate in order to locate said slacked portion therebetween due to said air stream provider blowing off said slacked portion, so as to interrupt light emission from said photo element to said light emitting element in order to detect where said slacked portion resides when skip of said stitches or disconnection of said sewing thread appears on said cloth material. 
 
     
     
       3. An automated skip checker device for sewing machine which has a sewing needle provided to form stitches on a cloth material, an engagement device provided to give a tension to an upper thread passing through a needle hole of said sewing needle as a sewing thread, and a thread take-up lever brought into engagement with said upper thread to reciprocally move in association with said sewing needle,
 said automated skip checker device comprising; 
 a tension provider which transfers a certain amount of tension to said upper thread in operation, so as to laterally curve said upper thread when a slacked portion appears on said upper thread, and 
 a detector device having a detection member provided to detect a position in which said slacked portion appears, said detector device locating said detection member within a thread route from said engagement device to a tip of said sewing needle; 
 said tension provider having a guide plate located on a line connecting said thread take-up lever to said sewing needle, 
 a vertical hole provided at a left side of said guide plate in order to pass said upper thread therethrough, and further having a suction air provider extending a vacuum pipe, a leading end of which is horizontally aligned with an opening which is provided at a right side of said guide plate to be in a crosswise communication with said vertical hole, so that the suction air provider suctions said upper thread through said vertical hole and said opening so as to continuously give vacuum pressure to said upper thread therethrough, and 
 said detector device having a light emitting element and a photo element which are space opposed by a distance outside the opening of said guide plate in a juxtaposed relationship with said opening of said guide plate in order to locate said slacked portion therebetween due to said vacuum pressure pulling said slacked portion out of said opening through said vacuum pipe, so as to interrupt light emission from said photo element to said light emitting element in order to detect where said slacked portion resides when skip of said stitches or disconnection of said sewing thread appears on said cloth material. 
 
     
     
       4. An automated skip checker device for sewing machine according to  claim 2  or  3 , wherein a warning system is provided to energize a control circuit which consecutively actuates an alarm bell during the time in which said light emitting element is interrupted at its light emission while continuously energizing an alarm lamp.